Medical professionals have long sought for a way to utilize ultrasound technology to help place intravenous catheters and needles in a patient more effectively. There often is a medical need to locate a blood vessel and to distinguish whether the blood vessel is a vein or an artery. For example, a vein is typically used for applying an intravenous (IV) medication, while an artery may be used for inserting a catheter to accomplish certain medical procedures. In addition, IV or catheter placement, and other medical therapies requiring blood collection, often present medical professionals with difficulties in pinpointing the exact location of a blood vessel. This can be due to many reasons including the patient's age, weight or complexion, and also the experience of the medical professionals who may be administering IV or catheter. The difficulties in locating and distinguishing a blood vessel are due in part to the fact that the current standard for locating blood vessels relies mainly on the touch and sight of the medical professional.
There are many factors that affect the visibility of the blood vessels. In turn, this can affect how many times a patient will have to be stuck with a needle. Obesity is one reason why it may be difficult to locate veins and arteries. Dehydration can also make it difficult for medical professional to locate a blood vessel to administer a medication to a patient via intravenous therapy. Other medical conditions such as venous thrombosis (a clogged vein), necrosis (death of tissue cells) and an embolus (air bubble in a blood vessel) can prohibit proper injection of medication using IV therapy or make it difficult to draw blood.
When the medical professional believes that an appropriate blood vessel has been located, he or she places a needle in the location of the blood vessel to perform the medical procedure. In many cases the medical professional may have been incorrect or that the needle may not have placed in a suitable blood vessel, thereby subjecting the patient to further needle sticks. For instance, of the over 1 Billion IV placements performed in the US each year, at least 300 Million placements will miss the blood vessel on the first attempt. And every failed needle stick subjects the patient to additional pain and injury.
There are numerous techniques that medical professionals typically use to help find blood vessels that are difficult to locate. These techniques aim to increase the visibility of blood vessels under the patient's skin. Options for assisting with intravenous (IV) and catheter placement have become available in recent years include infrared technology and modified sonograph machines. The current infrared devices require the medical professional to have the device held by another person while they place IV needle or a catheter into a blood vessel. Traditional sonograph machines can be very large, bulky, and stationary. Modified sonograph machines that only make use of a single transducer cannot distinguish whether the location is directly over a blood vessel or just off of an edge of the blood vessel, which can lead to an improper placement of an IV needle or catheter. Other sonograph machines may use techniques such as pulsed-wave Doppler (PW), which typically requires high-voltage (e.g., a driving signal at approximately 200 volts) and precision timing for the transducers, or continuous wave Doppler (CW), which requires a second set of transducers, which increases costs. Because of these reasons, among others, ultrasound and infrared technology has not widely been used for detecting and locating blood vessels.